US3865918A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Wet spinning cellulosic products
Assignee: TDK Micronas GmbH
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Filing: 1972-03-22
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Granted: 1975-02-11
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Expires: 1992-03-22
Abstract
Abstract Fibrous cellulosic products are prepared by extruding cellulose solutions through fiber forming devices. These fiber forming devices comprise porous extrusion media containing a controlled number and distribution of discrete flow paths. These flow paths constitute at least about 10 percent of the total extrusion surface area. The cellulosic fibers prepared by these processes exhibit unique and highly desirable physical and structural characteristics for use in forming new and improved nonwoven fabrics and disposables.
Inventors
- 👤 Reid L Mitchell
- 👤 Thomas E Muller
- 👤 Hugh D Stevens
- 👤 Robert S Tabke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:55
CPC Classifications
D; D04; D04H; D04H1/00; D04H1/40; D04H1/54; D01; D01D; D01D4/00; D01D4/02; D01F; D01F2/00; D01F2/06; D01F2/08; D01F2/24; D01F2/28
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
184 words
A PROCESS FOR PREPARING LOW-COST VISCOSE FIBERS HAVING PROPERTIES WHICH ARE SUPERIOR FOR NONWOVENS AND DISPOSABLES WITH RESPECT TO WATER ADSORPTION, WATER RETENTION, CROSSSECTIONAL SHAPE, FIBER ELONGATED AND TENACITY COMPRISING THE STEPS OF STEEPING DISSOLVING GRADE WOOD PULP IN A SODIUM HYDROXIDE SOLUTION; PRESSING, SHREDDING AND AGIGING SAID PULP TO PRODUCE AN ALKALI CELLULOSE CONTAINING ABOUT 32 TO 38 PERCENT CELLULOSE AND ABOUT 14 TO 16 PERCENT SODIUM HYDROXIDE AND HAVING AN AVERAGE DEGREE OF POLYMERIZATION LESS THAN ABOUT 400; XANTHATING SAID ALKALI CELULOSE WITH ABOUT 25 TO 30 PERCENT CARBON DISULFIDE AND DISSOLVING THE XANTHATE IN SODIUM HYDROXIDE TO PRODUCE A VISCOSE SOLUTION CONTAINING FROM ABOUT 7 TO 12 PERCENT CELLULOSE AND ABOUT 4 TO 6 PERCENT SODIUM HYDROXIDE; RIPENTING THE SOLUTION TO A SALT INDEX OF ABOUT 1.5 TO 7; DEACRATING AND SCREENING TH SOLUTION; AND EXTRUDING THE SOLUTION INTO CONTINUOUS FILAMENTS IN A COAGULATING BATH THROUGH A PORUS FIBER FORMING DEVICE COMPRISING A PORUS EXTRUSION MEDIA CONTAINING A CONTROLLED NUMBER AND DISTRIBUTION OF DISCRETE FLOW PATHS, SAID FLOW PATHS COMPRISING AT LEAST ABOUT 10 PERCENT OF THE TOTAL EXTRUSION SURFACE AREA.
Claim 2
Dependent Claim
184 words
A PROCESS FOR PREPARING LOW-COST VISCOSE FIBERS HAVING PROPERTIES WHICH ARE SUPERIOR FOR NONWOVENS AND DISPOSABLES WITH RESPECT TO WATER ADSORPTION, WATER RETENTION, CROSSSECTIONAL SHAPE, FIBER ELONGATED AND TENACITY COMPRISING THE STEPS OF STEEPING DISSOLVING GRADE WOOD PULP IN A SODIUM HYDROXIDE SOLUTION; PRESSING, SHREDDING AND AGIGING SAID PULP TO PRODUCE AN ALKALI CELLULOSE CONTAINING ABOUT 32 TO 38 PERCENT CELLULOSE AND ABOUT 14 TO 16 PERCENT SODIUM HYDROXIDE AND HAVING AN AVERAGE DEGREE OF POLYMERIZATION LESS THAN ABOUT 400; XANTHATING SAID ALKALI CELULOSE WITH ABOUT 25 TO 30 PERCENT CARBON DISULFIDE AND DISSOLVING THE XANTHATE IN SODIUM HYDROXIDE TO PRODUCE A VISCOSE SOLUTION CONTAINING FROM ABOUT 7 TO 12 PERCENT CELLULOSE AND ABOUT 4 TO 6 PERCENT SODIUM HYDROXIDE; RIPENTING THE SOLUTION TO A SALT INDEX OF ABOUT 1.5 TO 7; DEACRATING AND SCREENING TH SOLUTION; AND EXTRUDING THE SOLUTION INTO CONTINUOUS FILAMENTS IN A COAGULATING BATH THROUGH A PORUS FIBER FORMING DEVICE COMPRISING A PORUS EXTRUSION MEDIA CONTAINING A CONTROLLED NUMBER AND DISTRIBUTION OF DISCRETE FLOW PATHS, SAID FLOW PATHS COMPRISING AT LEAST ABOUT 10 PERCENT OF THE TOTAL EXTRUSION SURFACE AREA.
Claim 3
Dependent Claim
125 words
A process for preparing low-cost cellulose acetate fibers comprising the steps of preparing an acid solution of cellulose triacetate from a dissolving grade wood pulp by treatment with acetic acid and esterification with an acetic acid-acetic anhydride mixture in the presence of an acetylation catalyst; hydrolyzing said triacetate, at a temperature of from about 40* to 80* C., to an acetyl content of about 30-44 percent; screening the solution containing 10-15 percent cellulose acetate and 78-83 percent acetic acid and extruding said solution into continuous filaments in a coagulabting bath through a porous fiber forming device comprising porous extrusion media containing a controlled number and distribution of discrete flow paths, said flow paths comprising at least about 10 percent of the total extrusion surface area.
Claim 4
Dependent Claim
125 words
A process for preparing low-cost cellulose acetate fibers comprising the steps of preparing an acid solution of cellulose triacetate from a dissolving grade wood pulp by treatment with acetic acid and esterification with an acetic acid-acetic anhydride mixture in the presence of an acetylation catalyst; hydrolyzing said triacetate, at a temperature of from about 40* to 80* C., to an acetyl content of about 30-44 percent; screening the solution containing 10-15 percent cellulose acetate and 78-83 percent acetic acid and extruding said solution into continuous filaments in a coagulabting bath through a porous fiber forming device comprising porous extrusion media containing a controlled number and distribution of discrete flow paths, said flow paths comprising at least about 10 percent of the total extrusion surface area.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-10 | 1978-08-12 | 1979-02-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-10 | 1982-08-12 | 1983-02-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-10 | 1986-08-12 | 1987-02-11 | $7700.00 | Window Closed / Lapsed |